It's World IPV6 day today, with some of the biggest internet companies in the world testing deployment to IPV6 to make sure that the eventual transition will go off without a hitch.
The day has been organised by the Internet Society and is being backed by the likes of Google, Facebook and Yahoo.
Those who wanted to join in with the web test had to ask for permission before 3 June, but on the Internet Society's website you can test out your readiness for IPV6.
"The goal of the Test Flight Day is to motivate organisations across the industry – internet service providers, hardware makers, operating system vendors and web companies – to prepare their services for IPv6 to ensure a successful transition as IPv4 addresses run out," explained the Internet Society about the day.
Facebook said of the test: "World IPv6 Day will allow us to better understand how our infrastructure and code perform under IPv6 while minimising impact on our users.
"Since January, we've conducted several studies and tests of our own and have gained even greater confidence that our site is ready for IPv6."
The transition from IPV4 to IPV6 will free up more than 4 billion new web addresses.